Circuit breaker



L. SCHMIDT CIRCUIT BREAKER `lune 8, 1937.

2 Sheets-Sheet 1 Filed June 18, 1935 OR EY.

, INVENTOR. [aff/Hf ,f lf2/M June 8, 1937. SCHMIDT 2,083,509

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Patented June 8, 1937 I UNITED STATES PATENT OFFICE CIRCUIT BREAKERLambert Schmidt, Leeds, N. Y.

Application June 18, 1935, Serial No. 27,176

15 Claims. (Cl. 200-116) This invention relates to circuit breakers andhas for its object to provide certain improvements in circuit breakersof the type for which I now have pending an application for LettersPatent of the United States, Serial No. 702,153, dated December 13,1933. By means of these improvements in the case of a short circuit or aflow of electricity greater than that normally intended, the circuitcannot be permanently closed.v Such closing of the circuit brings abouta short circuit on the main circuit or burns out the parts of thecircuit breaker.

An object of this invention, accordingly, is to provide, in circuitbreakers of the above type, mechanism by means of which the breakercontacts may be maintained in an open position regardless of whethermanual pressure is exerted upon the closing mechanism or not.

A further object of the invention is to provide, in combination withmechanism of the above character, a free tripping mechanism which servesas a connection between the manual operating mechanism and the movablebreaker element, such mechanism rendering the connection between theseelements inoperative to maintain the breaker contacts in closed positionby continued manual mechanism.

A further object is to provide free tripping mechanism of the abovecharacter, the structure of which is independent of the structure of thecircuit breaker, thus enabling the breaker elements to be of suchconstruction that the breaker structure may be of minimum size.

A further object of the invention is to provide indicating means lbywhich a user may immediately detect whether or not an overload or shortcircuit is present. This indicating means Warns against operating thepush-button of the circuit breaker and therefore enables the user to seewhether or not the device is out of working order.

For this purpose an important feature of the invention lies in thefreedom of the operating rod of the circuit breaker under spring action,so that the circuit will not be permanently closed. This is accomplishedby giving the rod an unimpeded movement which will avoid the rod beingheld back and will enable it to be free to move without making permanentcontact; in other Words, a free tripping device is provided.

The invention consists in further providing indicating means operativein such cases where therod itself does not close the circuit and wherethe circuit is under current flow above thepredetermined normal amount.

pressure upon the starting The invention is shown as embodied in thestructure depicted in the drawings, and will be hereinafter more fullydescribed in the light of this embodiment, and iinally set forth in thesubjoined claims.

In' the accompanying drawings:-

Figure 1 is a vertical section taken through a circuit breaker showingmy improvements embodied therein;

Figure 2 is a plan view `or section taken on line 2 2 of Fig. 1;

Figure 3 is a section similar to that of Fig. 1, but showing onlycertain parts of the device shown in Fig. 1 and showing them indifferent operative positions Figure 4 is a perspective View of theguide springs or rod-holding device;

Figure 5 is a. partial side view ofthe piston sleeve to operate thespring iingers shown in Fig. 4;

Figure 6 is a side View of the rod which enters the sleeve of Figure 5and slides in respect thereto, and is either impeded by the spring ngersshown in Figure 4l or is left free to pass therethrough by the openingof the spring n'gers by the sleeve shown in Figure 5;

Figure 'l is a section of the parts 'shown in Figure 3 in differentpositions, and embodying a further improvement in the form oi' anindicating device;

Figure 8 is a side view ci an attachment plug of a different type 'thanthat shown in Figure 1, Figure 8 showing a thrust-in type of attachmentplug which is also an embodiment of the invention;

Figure 9 is a section view of another embodiment of the signallingdevice;

Figure 10 is a plan view taken on .line lil-I0 of Figure 9;

Figure 11 is a sectional view of another embodiment;

Figure 12 is a similar view taken at right angles tc that of -Figure 11;

Figure 13 is a sectional view of another embodiment of the thermostatccontrol which acts to hold the switch rod and also acts as a contactdevice;

Figure 141s a plan view taken on line |4-i4 of Figure 11;

Figure 15 is a plan view taken on line I5-l5 of Figure 11; and

Figure 16 is a plan view of a contact plate. Similar characters ofreference indicate corresponding parts throughout the various views.

Referring nowto the drawings, and more particularly to Figure 1, theplug casing I has a threaded portion II and a contact piece I2, as iswell known. Disposed within the plug casing i0 is a socket member I3 towhich is pivotally attached a sp'ring plate I4 having an opening I5, theedge of which opening is adapted to be engaged by the plug I6 on the rodII. When the plug I6 engages the edge of the opening I5, the rod |"I isheld in downward locked position. This locking device forms the basis ofmy above-mentioned pending application.

A thermostatic member I8 of horse-shoe form is supported by the studs|861., and this member is so arranged that when current in excess ofthat which can be considered normal, passes through the member I8 theiree end of the latter descends and the plate I4 is actuated in adownward direction. When this plate I4 is moved downwardly the edge ofthe opening I5 is dis-engaged from the plug I6 and the latter with therod I'I is free to move upwardly under the action of the spring I9 whichspring is seated in the bottom .of the socket portion and acts againstthe plug I6. 'The rod I'I has a contact member adapted to engage threeor more spring-like prongs indicated by 2|. When the contact member 20which is of plunger form, is forced into spring-like members 2| andengaged thereby and held in position therein, the electric currentpasses through the contact members, that is, the electric circuit isclosed when the member 20 engages the members 2|. The member 20 is heldin position within the springlike contact members 2| and the rod I`I hasits plug I6 locked by the spring plate I4, as above described. Upon theoperation of the horse-shoe member I8 by an excess current, the springplate unlocks itself by reason of the spring member I9 and the rod I'Iis forced upwardly whereupon the members 29 and 2| are disengaged andthe circuit is broken.

This unlocking action can also be accomplished by means of an externalpush-button 22, having a rod 23 which extends through casing I0 andthrough the recessed end IBD of the thermostatic member I8 to thespring-plate I4. Downward pressure on button 22 presses the plate I4downwardly and unlocks rod II. Thus rod I1 under its spring action, asabove described, may ascend and break the circuit.

It has been found that in cases where the thermostatic couple operatesto release the rod, the rod will again be presse-d downwardly and, whenthe parts are under an overload current, they burn out or short circuitresults. If a user repeatedly presses down on the push-button, as 25,short circuits in the entire system may result. To overcome this, myimprovement which forms the basis of the present application consists inthe following mechanism:

Spring fingers 26 provided with jaws 21, such as shown in Fig. 4, arearranged within the pushbutton 25. These spring fingers extend upwardlyfrom a base portion 28, which base portion seats in a suitable recess`29 at the lowermost portion of the push-button 25. A sleeve 30 has arounded end portion 3| (shown also in Fig. 5) and a plate 33. In theembodiment, the sleeve 30 is supported upon or is made integral with theplate 33 which is held to the casing I0 by screws 34, a spring 35 ofspiral shape being interposed between the plate 33 and the bottom of thepushbutton 25. This is clearly shown in Fig. 1, where the spring isshown in extended position, and in Fig. 3 where the spring is shown incompressed position.

The operation oi the embodiment described is explained as follows: Whenan excess of current acts upon the thermostatic couple I8, this memberis moved downwardly, whereby the plate I4 is unlocked from plug I5, androd l1 is free to move upwardly under the action of its spring I9. Ifthe push-button is now pressed down, the jaws 2l of the spring fingers26, will engage the flat end Ila of the rod il and move it downwardly.This downward movement of the rod i'I continues until the push-buttonarrives at a position wherein the bent portions 32 `oi the spring ngers26 meet the rounded portion 3| of the sleeve 30, through which the rodis free to slide. Upon further downward pressure applied to thepush-button 25, the rounded portion 3l opens the jaws 2l, and the rod Ilis free to pass therethrough. The spring i9 then forces the rod ilupwardly with great rapidity.' in the meantime, the contact member 20has made momentary contact with the contact member 2|, but this is onlyinstan-- taneous. The user pushing the push-button, can do so repeatedlyand each time the rod il will jump upwardly with great rapidity, and noharm can result therefrom. This result is predicated upon the fact thatthe overload acts upon the thermostatic couple I8 which in turn pressesthe spring rod downwardly to prevent the spring rod from locking the rodil. lin consequence oi the downward pressure of the push-button 25, therod is :First pushed down by the jaws 2l and then passes through thejaws 2l, as shown in Fig. 3, and while this causes the members 20 and 2|to contact, there is nothing to hold the rod in its downward position orto maintain it in its downward position, and therefore under the actionof the spring I9, it immediately and instantaneously jumps upwardlyuntil the plug IB reaches the plate 33. While Contact is made betweenthe contact members, it is insuflicient to cause a destructive current`to pass through the members 20 and 2|. By virtue o this arrangement ofparts, the push-button 25 can be pushed down repeatedly but the rod I1will always jump through and refrain from making a permanent electriccircuit, and therefore all danger of short circuiting to the system isobviated.

With the embodiment shown in Fig. 1, it may possibly be that the userwill continue to press down and cause rod I1 to be moved downwardly andinstantaneously jump back and at the same time wonder why no currentpasses through to light the lamp or the like, and in order to preventsuch repeated action, an indicating device is provided. An embodimentthereof is shown in Fig. 7, in which a plate 4D has two upwardlyextending rods 4| which pass through openings 42 in the top of thecasing I0, and upon these rods 4I enlargedfportions or buttons 43 of asuitable color, such as results from a bright bakelite, preferably red,are arranged. The plate 4U has a central opening 44 somewhat larger thanthe diameter of the rod I'I, so as to permit the rod I'I to freely movethrough said opening 44. A spring 45 is interposed be` tween the plate40 and the plate 33, which in this embodiment, has a shoulder portion 46in order to act as a seat for one end of the spring 45. In the normalclosed position of the device the plate 40 is ln'the position shown inFig. 7, that is, with the buttons 43 hidden in rtheir sockets 4'I. Theplate 40 is disposed immediately above the plug I 6 on the rod I'I, andon the upward movement of the rod I'I and its plug I6, the plate 49 iscarried along and thereby the buttons 43 are exposed exteriorly to thecasing, whereby they are visible. When visible, the user will see thedanger indication and will refrain from pressing down the button 25.-Thus when the plug I6 of the rod I1 presses upwardly against the plate33,l through the plate 40, the danger signal will be visible. When,however, the rod Il makesa permanent contact through the members 29 and2|, then vthe spring 45, presses the plate 40 downwardly, and thiscauses the signals 43 to disappear in their sockets.

When, however, the circuit is in a normal condition and the plate I8 isin its open position and it is desired to close the circuit, then l5 thepush-button 25 is pressed downwardly and the jaws 21 engage the nat endI 1a of the rod I1, whereby on the downward pressure of they push-button25 with the jaws 21 in contact with the flat end I'Ia of the rod I1, therod I1 is '20 pressed downwardly and the spring plate I4 locks the plugI5 in position, whereby the contact members 20 and 2| are made permanentand the circuit is closed.

From the foregoing, it will be seen that with 25 the arrangement of thesleeve 30 upon the rod I1, which sleeve has a roundedportion 3| to movethe jaws 21 outwardly and open the same. the rod II may freely move upand down without permanent engagement of the contact 30 members 20 and2|. On the other hand, when the rod I1 encountersthe jaws 21, thedownward pressure of the push-button 25 forces the contact members 2l)and 2| in permanent engagement with each other under the locked po- 35sition of rod i1. ,The current path through the foregoing mechanismflows from the shell Il to the lower post |8a in Figure 2 which is seenas being insulated from the plate I3. From this post the current flowsthrough element |8,

40 plate I3, rod I1 and contact terminals 20 and 2| to the centralcontact I2.

It is also to be noted that the arrangement of the plate with theindicating buttons 43 provides a very simple and assured means of indi-45 cati'ng a danger sign to the user of the device, in case eitherexcess current moves the member I8 downwardly against the plate I4, orthe rod 23 is pressed normally downwardly against the plate I4.

The various embodiments which have been described have been shown inconnection with Figure 1 as applied to a screw-threaded plug, but it isclear that instead of a screw-threaded portion, the thrust-in prongs maybe used in place 55 thereof, the mechanism described being as wellapplicable to the form shown in Figure 8, as to the form shown in Figure1.

In Figure 8, the casing 50 has a button 5| similar to push-button 25lwith circuit conduc- 60 tors 52 and 53, and with metallic contact prongs54 and 55.

A form of signalling device was described in connection with Figure '1.Another embodiment of the same is shown in Figure 9. A spring 65 plate80 is secured by the screw 8| to the casing IIJ. This spring plate 80has a bore 82, through which the rod I1 freely passes. The free end ofthe plate 89 has an opening 83, to enable al visible, either by beingush with the casing or extending slightly above it. The stud 84 can begiven a suitable color and, when visible, acts to signal that contact isbroken so as to tell the user not to keep on pushing the push button 25.The manual release 1| is shown, but needs no further description inconnection with this embodiment.

Another embodiment of the thermostatic control is shown in Figures 11 to16. 'I'he control now serves a triple function, first it acts' as athermostatic control, secondly, it acts to hold the switch rod, andthirdly, it acts as a contact.

The control 90 is placed on the bottom of the casing. It has enlargedspring plate portions 9|a fitted to frictionally and huggingly engagethe lower enlarged end 9| of the switch rod I1 when inserted therein.The control consists of two like parts,'each having one end securedtogether by an adjustable screw device 93. The parts may be manuallyseparated by a wedgelike member 94 on a pivoted elbow lever 95, actedupon by the exterior push button 1|, as shown in Figures 12 and 15. Toavoid arcing, a shunt contact device 96 is secured to the switch rod I1and this extends down to a high resistance stud 91 secured to thecontact plate 98 in electrical contact with the exterior contact plateI2.

The plate 98 has recesses IIlI engaged by tongues |02 of the control 98,and abuts against a shoulder |04. The plate 51 has diametrically arranged tongues or strips 61a formed into screwthreaded portions as seenin Figure 11, over which the screw-threaded socket li ts. When an excessof current passes through the control 90, it releases its hold on theenlarged part 9| of the switch rod I1, and permits it under the actionof its spring I9 to ascend and leave the control. Electrical connectionis still established through the rod 96 and stud 91. When the switch rodhas ascended sufficiently .so as to separate the end of the rod 96 andstud 91, then the ilnal interruption of electrical contact takes place.The arrow 99 in Figure 13 shows the direction of movement of the rodI'I. By this means, all injurious arcing is avoided at thev thermostaticcontrol 90. Vents |00 are provided in the casing I0 to permit the ow ofgas therethrough. The -ow of current through the device shown in Figures11 through I6 is from the shell I'I through wires 61a and plate 61 tothe shaft I1, contact member 9;, bi-metal element 9|, to the centralterminal The various embodiments justdescribed show the application ofthe different thermostatic control and contacts, in connection with thepush button action described in detail in the first part of thisspecii'lcation, and not repeated in connection with Figure 11.

The embodiment shown in Figure 9, is also embodied in the form shown inFigure 12.

The free tripping device then operates to insure against any repeateddownward pressing of the push button, because the signal 84 will bevisible to act as a warning. For instance, assuming an overload, afterthe plug 9| has engaged the control 90, this overload will release theplug 9| from the control 90, and move the rod |1 upwardly regardless inwhich position the push button finds itself, which gives the signa1 84by the plug I6 acting on the plate 89. When the push. button is thenpressed downwardly, the sleeve 30 opens the jaws 26 and the rod I1 canpass freely through the ngers 21. Hence, no matter how many times thepush button is pressed downwardly the rod is always released. The sameeect as just described in connection with an overload is naturallyattained when the push button 'il is pressed down to mechanically unlockthe control.

Having shown various embodiments of my invention and described the same,l do not wish to be limited to the particular embodiments described, asother forms may be proposed within the spirit of my invention as definedby the appended claims.

li claim:-

l. A circuit breaker having casing, a movable rod therein for making orbreaking the circuit, a spring plate for locking the rod in position, athermostatic plate ior operating the spring plate in case of overload; apush-button for operating the rod, said button having means for pushingthe rod in closed Contact position and permitting release of said rodfrom said contact position when the overload unlocks the rod while thebutton is pushed in.

2. A circuit breaker having a casing, a movable rod therein for makingor breaking the circuit, a spring plate for locking the rod in position,a thermostatic plate for operating the spring plate in case of overload;a push-button for operating the rod, said push-button having springfingers with jaws therein for engaging said rod, means in the path ofsaid spring fingers 'for opening said jaws and permitting the rod topass therethrough when unlocked by the spring plate.

3. A circuit breaker having a casing, a movable rod therein for makingor breaking the circuit, a spring plate for locking the rod in position,a thermostatic plate for operating the spring plate inv case ofoverload; a plug on said rod to engage the locking spring plate, aspringdisposed between said plug a fixed part of the casing, a fixedsleeve supported by the casing having a bore for the passage oi the rod,a push-button having spring nngers with jaws, said jaws being adapted toengage the end oi the rod passing through the spring fingers, said `iawsbeing adapted to be opened to permit the passage therethrough of therod, upon the jaws riding on said fixed sleeve upon the movement oi thepush-button in respect'thereto, whereby upon the presence of an overloadthe rod is free to move between the jaws and to be forced by its springout or contact with the circuit.

4. A circuit breaker having a casing, a movable rod therein for makingor breaking the circuit, a spring plate for locking the rod in position,a thermostatic plate for operating the spring plate in case of overload;a push-button for operating the rod, said b`uttonhaving means forpushing the rod in closed contact position and permitting release ofsaid rod from said contact position when the overload unlocks the rod, aplate Within the casing and an indicator on said plate normally withinthe casing, said plate being moved by the rod to force the indicatorinto an indicating position, when said rod is unlocked from the springplate.

5. A circuit breaker having a casing, a movable rod for making orbreaking the circuit, means to urge the rod into an open circuitposition, a push-button for operating the rod, said button having meansfor pushing the rod into a circuit-making position, means for movingsaid aoeasoe 6. Means for breaking an electric circuit comprising acasing, a movable member therein for making or breaking the circuit,means for urging the member into an open circuit position, means forholding the member in and releasing it from a closed circuit position,means for moving the member into circuit closing position, and meansmounted on the casing within the path of the means for moving the memberinto circuit closing position for rendering the lastnamed meansinoperative, said last-named means being independent of the structure ofthe means for breaking the circuit.

'7. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in and releasing it froma closed circuit position, means ior moving the member into circuitclosing position, and means rendering the last-named means inoperative.

8. A circuit breaker having a casing, a movable member therein or makingor breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a closed circuitposition, thermostatic means for releasing the holding means, means formoving the member into circuit closing position, and means operativeduring the flnal closing motion of the member to render the lastnamedmeans inoperative.

9. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a closed circuitposition, thermostatlc means for releasing the holding means, yieldingmeans for moving the member into circuit closing position, and meansrendering the last named means inoperative.

iii. A circuit breaker having a casing, a movable member thereln formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a closed circuitposition, thermostatic means ior releasing the holding means, anoperating member, means movably mounted on the operating member forengaging the movable member to transmit motion from the operating memberthereto, and means to disengage the last named member from the movablemember.

ll. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a closed circuitposition, thermostatlc means for releasing the holding means, anoperating member, means movably mounted on the operating member forengaging the movable member to transmit motion from the operating memberthereto, and means operative during the final motion of the movablemember into circuit closing position to dlsengage the last named memberfrom the movable member.

12. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a. closed circuitposition, thermostatlc means for releasing the holding means, anoperating member, means movably mounted on the operating member forengaging the movable member tc transmit motion from the operating memberthereto, and a shouldered member on the casing to dlsengage the lastnamed member from the movable member during nal closing motion of themovable member. l

13. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding t'ne member in a closed circuitposition, thermostatic means for releasing the holding means, anoperating member, means movably mounted on the operating member forengaging the movable member to transmit motion from the operating memberthereto, a sleeve on the casing through which the movable member moves,and a shoulder on the sleeve in the path of the last named member toengage the same and disengage the said last named member from themovable member.

14. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a closed circuitposition, thermostatic means for releasing the holding means, means formoving the member into circuit closing position, means rendering thelast named means inoperative, an indicator, means to mount the indicatorin the casing to be yieldingly urged into a nonindicating position, andmeans to move the indicator into an indicating position by the movablemember.

15. A circuit breaker having a casing, a movable member therein formaking or breaking the circuit, means for urging the member into an opencircuit position, means for holding the member in a closed circuitposition, thermostatic means for releasing the holding means, a springpressed push button, yielding means on the button for engaging themember to move the member into circuit closing position, and means onthe breaker to disengage the yielding means from the member during thenal closing motion of the latter.

` LAMBERT SCHMIDT.

